The invention relates to a cylinder lock-key-combination, a key blank intended for the combination and a key intended for the combination and made from the key blank.
In growing markets great numbers of opening combinations for selected lock mechanisms and/or additional new key profiles are needed for large groups of locks to be masterkeyed, which can be distinguished from earlier key profiles already provided for the markets and which can be utilized for keeping the different lock groups separate from each other. A key profile refers here to the form of a key before any combination surfaces or combination cuts required by the actual opening combination of the lock are made. For big applications it may even be necessary to provide dedicated key profiles. In addition depending on the application different key profiles should be available on the one hand for locks operated in only one turning direction and on the other hand correspondingly also for bidirectionally operable locks. The turning direction or operating direction of a lock refers here to the direction in which the key turns for opening the lock mechanism. Since cylinder locks provided with so-called rotatable locking discs are advantageous from the viewpoint of their masterkeying and pickproof properties, the new key profiles should be suitable for particular lock mechanisms of this kind.
A bidirectionally operable cylinder lock provided with rotatable locking discs and having a symmetrical key which may be inserted in the lock in two different turning positions is known from U.S. Pat. No. 4,351,172. This lock can be adapted also to be operable in only one turning direction, but this requires positively blocking one of the turning directions by means of a separate blocking member. A more recent cylinder lock is known from U.S. Pat. No. 5,490,405. This lock is operable in only one turning direction and the returning of the locking discs is accomplished by making use of a separate returning member, whereby more space is obtained in the shank of the key for different profile grooves. In this lock the opening for the key in the locking discs is additionally designed in a certain way so that for example a key according to a practical implementation of U.S. Pat. No. 4,351,172 is not operable in the lock shown in U.S. Pat. No. 5,490,405. Hereby, by means of this solution a key profile family of its own is provided which is independent of earlier key profiles.
Also the patent FI 25618 shows a bidirectionally operable lock in which the selection of the direction of operation occurs by means of a separate guiding plate located in front of the set of discs. In this solution, in the key opening of the locking disc there is a counter surface for each possible combination cut. In addition the key itself comprises a key shank having a separate bit part for combination cuts, which is in clear contrast to the keys according to the solutions mentioned above. Thus the key inserted in the lock is available for only one turning direction at a time and in addition the opening combination is identical for both turning directions.
An aim of the invention is to provide a novel cylinder lock-key-combination, new keys intended therefor as well as key blanks for the keys, suitable particularly for locks provided with rotatable locking discs and making it possible to provide new key profiles which are operationally independent of prior known key profiles. An aim is additionally to provide a solution offering versatile possibilities for adapting the invention in view of different needs for locking so that it may easily be adapted to locks operable on the one hand in one turning direction and on the other hand in two turning directions. In addition the solution should be uncomplicated, secure as to its operation and advantageous as to its costs.
In accordance with the invention the key opening of at least one locking disc has at least two discrete counter surfaces for effecting turning of the locking disc in one direction, and these counter surfaces are so dimensioned and arranged with regard to each other that at least two different combination values can be alternatively selected for the corresponding combination surface of the key. Different combination values refer to the possible different turning angles through which the key turns the locking discs in order to open the lock mechanism. In accordance with the invention a simple and well-defined design is obtained for the key opening of the locking disc which may effectively be utilized in cooperation with the combination surfaces of the key having a key profile of clearly different design from those previously known. In addition the same basic solution may with advantage be adapted both for cylinder locks operable in one direction and for cylinder locks operable in two directions.
The technical effect of the solution can further be improved when the key opening of a code locking disc which can be provided with different combination values has two counter surfaces for one turning direction of the key, and the two counter surfaces are angularly spaced from each other about the turning axis of the locking disc and are disposed at different respective angles to the central axis of the key opening of the locking disc so that they are inclined at an angle of about 30xc2x0. The central axis of the key opening extends in the plane of the locking disc as distinct from the turning axis of the locking disc, which is perpendicular to the central axis of the key opening and passes through the center of the key opening.
When the counter surface in the key opening of the code locking disc corresponding to larger turning angles of the key extends substantially to the central normal of the central axis of the key opening, the key opening may in a simple way be made fully symmetrical for a bidirectionally operable lock or partly symmetrical for a unidirectionally operating lock. In both cases the counter surfaces and/or return surfaces for the same turning direction are diametrically located with regard to the turning axis of the locking disc.
The key openings of the code locking discs can with advantage be at least substantially identical and formed so that some degree of free turning of the key is provided, i.e. the code locking discs turn with the key only after the key has been turned to some degree, for instance about 15xc2x0, from the initial insertion position of the key. The lock includes further at least one lifting 0-locking disc of which the key opening is smaller than the key opening of the normal code locking discs and which always turns when the key is turned in the lock. The basic aim of a lifting 0-locking disc is to provide for returning of the locking bar into its locked position under positive guidance when the lock mechanism is locked. No code locking disc has in this case the 0. combination. Consequently, the combination values of the code locking discs determining the opening combination of the lock are totally independent of the 0-locking disc and its counter surfaces, which increases the number of opening combinations available and improves the masterkeying properties of the solution according to the invention. In addition the lifting 0-locking disc may naturally be utilized for defining the profile of the key shank compatible with the key channel and to arrange for desired variations thereof for providing different lock families.
When the lock is operable in only one turning direction, the surface of the key opening of a code locking disc opposite to the counter surface with regard to the central axis serves as a return surface, which in cooperation with the key is used to return the locking discs to the locking position of the lock mechanism. By arranging the return surface in the same plane as one of the counter surfaces of the locking disc a simple and well-defined form is obtained for the key opening. The solution is secure as to its operation and no separate return members are needed in it.
When the lock is operable in both turning directions the code locking disc has in total four counter surfaces for each turning direction, the counter surfaces serving for the same turning direction being located in pairs diametrically on either side of the turning axis of the locking disc.
The basic form of the shank of a key blank according to the invention in the perpendicular cross-sectional plane of the shank, exclusive of any possible profile grooves or corresponding grooves extending over the shank, is substantially rectangular except for at least one bevel surface at one or more corners for providing at least one combination surface. Hereby the basic form of the shank of the key blank is simple and advantageous to manufacture.
Advantageously the bevel surface provides selectively one of two combination surfaces having different respective combination values. In this way the number of different combination values normally to be utilized in this lock type can easily be obtained without compromising the security of operation for opening the lock. The length of the individual combination surfaces may be shorter than in a conventional lock. On the other hand the solution makes it also possible to increase the number of combination values, which provides for multiplying the opening combinations available.
In practice the bevel surface forms in the perpendicular cross-sectional plane of the shank of the blank an angle of 20xc2x0-30xc2x0, preferably an angle of about 25xc2x0, with the central axis extending in the direction of the longer side of the rectangular cross section of the shank. The bevel surface may be divided into two parts which extend mutually in different directions and each of which forms one combination surface. Alternatively the bevel surface may be divided into two at least substantially parallel parts separated from each other by a step or the like and each forming one combination surface. Hereby manufacturing of illicit keys may be made more difficult. In addition hereby an entirely new family of key profiles can be provided.
By arranging the shank of the key blank to be symmetrical as to the parts located diametrically opposite each other with regard to the central axis of the shank so that there is a bevel surface at each of two diametrically opposite corners, the key can be inserted in the lock in two different turning positions. In the case of a lock operable in both turning directions each corner of the shank of the key blank may be provided with a bevel surface so that the shank of the key blank is symmetrical with regard to both the central axis parallel to the perpendicular cross-sectional plane of the shank and its central normal. When on the other hand the key blank is intended for a lock operable only in one turning direction the bevel surface at every second corner of the shank may operate as a return surface for the locking discs.
The invention relates also to a key for a combination defined above and to be made from a key blank defined above, which is characterized in that the basic form of the shank of the key blank in the perpendicular cross-sectional plane of the shank, exclusive of any possible profile grooves or corresponding grooves extending over the shank of the key, is substantially rectangular except for at least one bevel surface at one or more corners and providing combination surfaces corresponding to the code locking discs of the lock. The bevel surface provides at least one selectable combination surface, and the value of other successive combination surfaces in the key is determined on the basis of the combination of the angle of cutting and the length of the cut surface of the cuts to be made in the bevel surface.
The bevel surface may with advantage comprise two combination surfaces having different combination values. In this case the angular pitch between cuts corresponding to successive combination values may respectively be about 15xc2x0, which is sufficient to secure reliable operation of the lock and makes it possible to utilize a 0-cut only for the lifting 0-locking disc independent of the combination values to be given for the code locking discs.
In a favorable embodiment of the key the length of the cut surfaces corresponding to different combination values is determined so that the extreme or outer ends thereof are located at most on three different peripheral surfaces measured from the central axis of the shank of the key. A peripheral surface means here not only an arc of a circle or other curved surface but also a plane or possibly a surface including even several separate plane parts. Correspondingly the extreme ends of the cut surfaces providing for turning movement for the locking discs and corresponding to different combination values are with advantage located on two different peripheral surfaces measured from the central axis of the shank of the key. In this case the combination surfaces extending to the same peripheral surface are with advantage located mutually with equal pitch, which makes manufacturing of the key simpler. However, the mutual angular pitch between successive combination surfaces located on different peripheral surfaces need not be in accordance with the pitch in question, but it is sufficient that the mutual pitch between the counter surfaces in the code locking disc is selected to operationally correspond to said angular pitch between successive combination surfaces located on different peripheral surfaces, so that the turning movement imparted to a code locking disc by means of the key is operationally compatible with the location of the peripheral notch of the code locking disc.
The parts of the combination cuts diametrically opposite each other with regard to the central axis of the shank of the key are with advantage located symmetrically, whereby the key can be inserted in the lock in two turning positions. In addition in the case of a bidirectionally operable lock the key includes four cut surfaces for each code locking disc so that the combination cuts located diametrically opposite each other with regard to the central axis of the shank of the key are identical.